\documentclass{article}
\usepackage[x11names, rgb]{xcolor}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{snakes,arrows,shapes}
\usepackage{amsmath}
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\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\setlength\PreviewBorder{0pt}%
\usetikzlibrary{automata}%

\begin{document}
\pagestyle{empty}
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%
%

\enlargethispage{100cm}
% Start of code
\begin{tikzpicture}[>=latex',join=bevel,]
\tikzstyle{every state}=[draw=blue!50,very thick,fill=blue!20]%
\node (q0) at (195bp,282bp) [state] {$\{q_{4},q_{0}\}$};
  \node (q3) at (171bp,18bp) [state] {$\{q_{3}\}$};
  \node (q1) at (62bp,194bp) [state] {$\{q_{1}\}$};
  \node (q2) at (27bp,106bp) [state] {$\{q_{2}\}$};
  \draw [->] (q3) ..controls (235bp,25bp) and (298bp,36bp)  .. (312bp,54bp) .. controls (325bp,70bp) and (324bp,228bp)  .. (312bp,246bp) .. controls (302bp,259bp) and (262bp,269bp)  .. node[auto] {$\overline{PA_And_User_PLink#Complete_People_Activity}$} (q0);
  \draw [->] (q0) ..controls (155bp,267bp) and (133bp,257bp)  .. (116bp,246bp) .. controls (104bp,238bp) and (92bp,227bp)  .. node[auto] {$PA_And_Start--004_PLink#Start$} (q1);
  \draw [->] (q1) ..controls (50bp,164bp) and (43bp,147bp)  .. node[auto] {$\overline{PA_And_User_PLink#Receive_Task}$} (q2);
  \draw [->] (q2) ..controls (16bp,77bp) and (15bp,63bp)  .. (22bp,54bp) .. controls (37bp,37bp) and (95bp,27bp)  .. node[auto] {$PA_And_User_PLink#Complete_People_Activity$} (q3);
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\end{tikzpicture}
% End of code

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\end{document}
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